Good point, Skans. The vendors are paying to sell something, as well.
I never buy anything on my first trip around a show, unless it's a steal. Saves me from impulse buys I might regret later.
I don't take any trading stock along on the first round. Saves me time dealing with the 'Wachu got/Whachu want?/Giveu hunnerd bucks' goobers.
I don't act particularly interested in guns I'd otherwise drool over. The first round is a recon mission, pure and simple. I compile a mental list of items and locations and I decide what I'll give/trade for them. Then I get after it.
Word to the wise- an awful lot of junk gets unloaded at gun shows. Look over your prospective purchases real hard. Some vendors won't like this much. Don't argue, just set it down and move on.